Figure 6.

BIPep reduces AR residence at AREs, limits AR activity, and suppresses AR-dependent prostate cancer cell proliferation. A, LNCaP cells were transfected with H2B-GFP and either pcDNA3 or pcDNA3-BAF57 1-145-3Xflag. After transfection, medium was changed to steroid-free conditions for 48 h. Cells were stimulated with 10 nmol/L DHT for 1 to 2 h and subjected to immunoblot analysis for flag, BAF57, or AR (left) or ChIP analysis for AR recruitment to the PSA enhancer region (middle). Ten percent input and AR recruitment are shown for the 1-h time point. Right, as shown by quantification of relative AR recruitment using real-time PCR, these findings were recapitulated at the 2-h time point. B, BT549 cells were transfected with pARR2-Luc, pTK-Renilla-Luc, pSG5AR, pBabe-BAF57-flag, and pcDNA3-BAF57 BIPep as indicated. Treatment and reporter analysis were carried out as in Fig. 4B. DHT-stimulated AR plus BAF57 is set to 100 and data are presented as relative light units. *, P < 0.05. C, LNCaP cells were transfected with H2B-GFP and plasmid encoding pcDNA3 vector, pSG5ARΔ46-408 (dnAR), or pcDNA3-BAF57 BIPep 3Xflag. Reverse transcription-PCR was performed for PSA, TMPRSS2, or GAPDH. Left, representative data. Quantification of relative PSA or TMPRSS2 expression (relative to GAPDH, with expression levels for vector-transfected cells set to “1”) is shown. D, LNCaP cells were transfected with H2B-GFP and pcDNA3, pSG5ARΔ46-408 (dnAR), or pcDNA3-BAF57 BIPep 3Xflag. Left, BrdUrd analysis was performed; right, parallel experiments were performed for PC-3 cells. Results from at least three independent experiments (each experiment with at least two to three independent biological replicates) are plotted as percent inhibition of BrdUrd incorporation over vector control. **, P < 0.01.